Apparatus for indicating consumption of liquid fuel.



' W. BOWDEN. APPARATUS FOR INDICATING CONSUMPTION 0F LIQUID FUEL.

APPLICATION FILED AUG- H. i913- 1,181,566. Patented May 2, 1916.

2 SHEETS-SHEET I.

W. BOWDEN.

APPARATUS FOR INDICATING CONSUMPTION 0F LIQUID FUEL.

APPLICATION FILED AUG-8. I913.

1, 181 ,566, Patented May 2,1916.

2 SHEETS-SHEET 2.

HIIIIIIIIHIIIIIIHI III" q/jtncsscs; nvcntor:

UNITED STATES PATENT OFFICE.

WIL LLAM BOWDEN, OF MANCHESTER, ENGLAND.

- APPARATUS FOR INDICATING CONSUMPTION OF LIQUID FUEL Specification ofLetters Patent.

Patented May 2, 1916.

Application filed August 8, 1913. i Serial No. 783,773.

To all whom it may concern:

Be it known that 1, WILLIAM Bowman, a subject of the King of GreatBritain and Ireland, and a resident of Manchester, in the county ofLancaster, England, have in vented new and useful Apparatus forIndicating Consumption of Liquid 'Fuel, of which the following is aspecification.

This invention relates to apparatus for giving of liquid fuel forinternal combustion engines in conjunction with a, reading of the speedof a motor car driven by such engines, so that by comparison of thereadings it can be easily ascertained whether the rate of fuelconsumption is or is not in excess of that which is normal to the speedof the car.

In carrying this invention into effect an instrument is employed whichis so constructed and connected to the carbureter that its pointer orequivalent part will vary its position as the atmosphericpressure in thechoke pipe of the carburetor varies. The at: mospheric pressure in thechoke pipe is governed by the throttle valve and governs or controls therate of flow of fuel through the jet of the carbureter. As thisatmospheric pressure varies the rate of fiow varies. The instrument thepressure in the carburetor choke tube, .will' also, therefore, give anindication of the rate 'of flow of fuel through the carbureter jet. Suchan instrument I will hereinafter refer to as a fuel consumptionindicator.

It can easily be ascertained by experiment what flow of fuel per timeunit will take place under the atmospheric pressure conditions set up inthe carbureter by the suck of the engine when driving the car at anygiven speed under normal conditions. The point where the needle orpointer of the fuel consumption indicator comes to under such pressureconditions is then marked on the scale with the rate of flow of fuel pertime unit which then obtains. Variations of pressure in the carburetorchoke tube produce variations in the position ofthe needle or pointer,and each of these variations of position is marked to indicate the, rateof fuel flow which ensues for the corresponding variation in pressure towhich the carbureter jet is exposed. To ascertain whether the fuelconsumption is or is not normal for any speed of the car, the reading ofthe fuel consumption indicator has to be compared a reading of the rateof consumption above referred to, in indicating with a reading or anestimate of the speed of the car.

The accompanying drawings illustrate an instrument in which aspeedometer is combined with a fuel consumption indicator whose readingsof the variations of pressure at the jet of the carbureter are expressedin terms of the rate of liquid flow which ensues as a result of suchvariationsq-a Figure 1 illustrates the complete apparatus partly inelevation and partly-,in'section. Fig. 2 shows the apparatusin plan.Fig. 3 is an elevation to a larger scale'of the same instrument. Fig. 4shows in plan a modification of the instrument. Fig. 5,

shows a longitudinal section through the in strument, and, Fig. 6 arearfqievation of the instrument with the back removed.

A indicates a jet carburetor of any ordinary construction with thecustomary float chamber .B.

C is the customary throttle.

D is a small pipe opening into the choke tube A of the carbureter asindicated.

Referring first to Figs. 1, 2 and 3, E is the fuel consumption indicatorconsisting of a pressure indicating gagejto wh'ch the other end of thetube or. pipe B is operatively attached. The fuel consumption indicatoris disposed-below a speedometer F of usual construction and operation.The separate index needles of the speedometer and of the fuelconsumption indicator have independent angular 1 movement around acommon center. The light rod G from the diaphragm H of the fuelconsumption indicator operates the quadrantkJ and pinion K to giveangular movement to the finger L shown in one of its positions in brokenlines L in Fig. 3. The needle ,M of the speedometer which is operated inthe usual way is also indicated in one of its-positions M in brokenlines in Fig. 3. The fuel consumption indicator needle L moves along ascale marked in gallons per moves along the usual speed scale markedinmiles per hour.

The instrument shown in Fig. 3 is for a car which, running under normalconditions, would travel '20 miles. on a consumption of one gallon offuel, and would under like normal conditions consume greater or lesserquantities of fuel per hour as the speed increased or decreased; Withsuch a car and with everything normal the speed ometer needle wouldindicate 20 when the hour. The needle M gallons per hour scale. The 20mark on the speed scale and the 1 mark of the consumption scale will bein the same radius. With the speedometer needle at 20 and the fuelconsumption indicator needle at 1, one needle would lie over the otherand there would apparently be only one needle in view. This wouldindicate that everything was correct. If the .fuel'consumption indicatorneedle was in advance, along its scale, of the speedometer needle itwould indicate.

that .an excessive consumption of fuel was taking place; if it laggedbehind it would indicate that an economy in fuel was being effected. Forexample the indication shown by the needles in broken lines in Fig. 3would show that a. very excessive consumption of fuel was taking place.Speed indi cations and their corresponding consumption indications arein common radii.- To prevent rapid oscillations of the fuel consumptionindicator needle as a result of rapid fluctuations of pressure in thechoke tube A, the tube D is preferably provided with a tap N by means ofwhich the air passage into the gage can be so choked that the rapidfluctuations of pressure .in the choke tube A do not materially affectthe diaphragm H and such diaphragm is only deflected to anextent whichresults from the mean pressure of the fluctuations. When desiredhowever, the tap N can be fully opened so as to get the most extremeoscillations of the gage needle.

A modified form of instrument is shown in Fig. 4. In this the diaphragmH of the fuel consumption indicator is arranged at the back of the jointinstrument, normally parallel to the dial. The speedometer needle M isoperated in the usual way. The hub of the fuel .consumption indicatorneedle L is formed with a small coarsely pitched screw nut O. Acorresponding screw thread which engages with such nut is cut on the endof the non-rotatable shaft G projecting from the center of thediaphragm. As the shaft G moves axially owing to diaphragm deflectionsthe nut and the finger L turn angularly.

Other forms of fuel consumption indicator than the corrugated diaphragmform may be used. In Figs. 5 and 6 there is shown one in which acollapsible chamber or bellows P is in communication with the choke tubeof the'carbureter by means of the pipe D. The rigid end wall H of thiscollapsible chamber is provided with a projecting member 1 which passesbetween and engages with one side of the prongs of a forked lever Q bymeans of the collar 2 formed on it. When the pressure in the chamber Pis reduced, the end wall H of the collapsible chamber moves inward and.carries the lever Q with it, the forked end of the lever allowing thismovement. When the pressure in chamber P increases the end H of thechamber moves outward as a consequence of the pressure exerted by thespring 3 on the lever Q. The lever Q is secured to the oscillating shaftR which also has secured to it the lever G; these two levers act as thelimbs of a bell-crank lever oscillating on the shaft R. The end of thelever G is connected to the quadrant J by means of the link 4. When therigid end wall H of the collapsible chamber P moves,

its movements in either direction are im- K on which is attached thefuel consumption indicating finger. The speedometer shown in thesefigures is, by way of example, of the centrifugal type. spindle S isrotated from the shaft T driven from the road wheel of the car throughthe gearing T, the weights S fly outward and raise the sleeve S providedwith annular' teeth which mesh with the pinion U on the shaft U and movethe speed indicating finger M over the. scale.

Other forms of carburetor than the jet form can be similarly connectedto the vacuum gage.

In addition to being used for indicating the rate of fuel consumptionduring the running of the car, the fuel consumption indicator may beemployed to give an indication as to whetherthe consumption is or is notnormal while the engine is running slow and the car is at rest. It havinbeen ascertained what position the nee 16 L would occupy under suchconditions, its then position is marked in a. distinctive shape or coloras for example as shovn at m Fig. 3. Should the needle L move past a:when the engine is running under the indicated conditions it is awarning that something is wrong.

What I clalm is An instrument for indicating the speed of a vehicledriven by an internal combustion engine having a carbureter, and forindicating the fuel consumption of such engine, comprising a casing, adial secured As the thereto and provided with two concentric scales, onescale being calibrated toindicate the speed of the vehicle and the otherto indicate the fuel consumption of the engine, an indicator for thespeed scale, means responsive to the speed of said vehicle for operatingsaid indicator, an indicator for the fuel consumption scale, a chamberhaving a movable wall and secured in said 10 casing, means operativelyconnecting said Wall to the last named indicator, and means forconnecting said chamber to the choke tube of the carbureter of saidengine.

In witness whereof I have hereunto set my hand in the presence of twosubscrib- 15

